Characterization of atomic and molecular impurity sources and transport at the tokamak edge

The characterization of impurity sources in the tokamak edge is challenging because of the highly localized nature of impurity generation. Detailed, spatially resolved, diagnostic information is needed, and three-dimensional (3-D) modeling is required for interpretation. There is also a need for a more extensive atomic and molecular data base for the conditions encountered in this region. The availability of new measurements of photon efficiencies for some relevant hydrocarbon molecules for plasma conditions typical for the tokamak edge and the development of a 3-D Monte Carlo impurities code have enabled the successful modeling of spatially resolved measurements in the vicinity of the pump limiter neutralizer plate and near the inner wall of Tore Supra

Churn, Baby, Churn: Strategic Dynamics Among Dominant and Fringe Firms in a Segmented Industry

This paper integrates and extends the literatures on industry evolution and dominant firms to develop a dynamic theory of dominant and fringe competitive interaction in a segmented industry. It argues that a dominant firm, seeing contraction of growth in its current segment(s), enters new segments in which it can exploit its technological strengths, but that are sufficiently distant to avoid cannibalization. The dominant firm acts as a low-cost Stackelberg leader, driving down prices and triggering a sales takeoff in the new segment. We identify a “churn” effect associated with dominant firm entry: fringe firms that precede the dominant firm into the segment tend to exit the segment, while new fringe firms enter, causing a net increase in the number of firms in the segment. As the segment matures and sales decline in the segment, the process repeats itself. We examine the predictions of the theory with a study of price, quantity, entry, and exit across 24 product classes in the desktop laser printer industry from 1984 to 1996. Using descriptive statistics, hazard rate models, and panel data methods, we find empirical support for the theoretical predictions

The Evolution of Grocery Wholesaling and Grocery Wholesalers in Ireland and Britain since the 1930s

Studies of industry evolution are relatively scarce outside of industries defined by narrow technological bases. Studies of wholesaling are rarer still. These are curious features given that it is probable that service industries behave differently to manufacturing ones and that wholesaling is such a key function of many economies. This paper looks at the evolution of grocery wholesaling and grocery wholesalers in Ireland and Britain since 1930. It focuses on the processes and drivers of the wholesale industry. Similarities and differences between the two countries are discussed. Particular emphasis is placed on the role of government action as a triggering mechanism for change and on the role of trade associations and industry leaders in developing and following through on market and non-market strategies. The pathways of industry evolution identified differ from those seen in manufacturing. They therefore raise a number of issues for the development of understanding and conceptualisation in industry evolution studies

Innovation and the creative destruction of trade : a study of the intensive and extensive margins of trade for French firms

Our study of French exporters examines the causal relationship between innovation and extensive and intensive margins of trade using a propensity score matching and difference‐in‐differences approach. Results show innovation has a positive impact on total exports driven primarily through the intensive margin. To understand the absence of an extensive margin effect, we show new and terminated product–country transactions increase at similar rates in the year of innovation for the treated and control groups but net trade creation for innovators outstrips that of non‐innovators in the following two years implying firms need to innovate in order to survive in export markets

Isospin Dependence in the Odd-Even Staggering of Nuclear Binding Energies

The FRS-ESR facility at GSI provides unique conditions for precision measurements of large areas on the nuclear mass surface in a single experiment. Values for masses of 604 neutron-deficient nuclides (30<=Z<=92) were obtained with a typical uncertainty of 30 microunits. The masses of 114 nuclides were determined for the first time. The odd-even staggering (OES) of nuclear masses was systematically investigated for isotopic chains between the proton shell closures at Z=50 and Z=82. The results were compared with predictions of modern nuclear models. The comparison revealed that the measured trend of OES is not reproduced by the theories fitted to masses only. The spectral pairing gaps extracted from models adjusted to both masses, and density related observables of nuclei agree better with the experimental data.Comment: Physics Review Letters 95 (2005) 042501 http://link.aps.org/abstract/PRL/v95/e04250